The too tight French top nut for the English stem will booger up and weaken the stem. I have a 21-23 mm adjustable reamer that's made for that purpose. If you need help, you pay postage and I'll size it for free. Also the Eng threaded BB on older Frenchies. Swiss is opposite threaded like Eng. but a scant .004-5's different diameter. I have one bike that's French on one side and Eng on the other, because someone boogered it up with Eng cups. That's why I got all the taps, dies, and reamers necessory to clean up things. Dickey Greer West Monroe,La USA